The present invention relates to a three-dimensional display system and more particularly to an advertising or other type of display sign which presents an apparent view in depth on a surface which is essentially two-dimensional and therefore presents the impression of a three-dimensional view of a composite scene. Essentially, the present invention contemplates the utilization of a mirror or other suitable reflective surface on which a foreground scene is placed, either by directly marking, printing or painting the same on the mirror or by laying a transparency carrying the foreground scene on the surface of the mirror. The mirror is at an appropriate angle to a light box having a source of diffused light on which a transparency may be placed through which the diffused light is transmitted. The transparency carries an appropriate background scene. The mirror is at an acute angle to the upper surface of the light box that the light with the background image transmitted thereby will be reflected from the mirror in a direction calculated to be most likely to be intercepted by a viewer.
It has been found that the combination of the light box with a background scene transmitted by diffused light therefrom to the mirror and the mirror carrying at its front surface the foreground scene produces an unexpected and startling effect creating an impression of depth and consequently creating a three-dimensional effect.
Ordinarily, three-dimensional effects are supposed to occur because of human binocular vision. However, with the interocular distance of the order of only three inches, the base line for obtaining an appreciable difference in the images received is such that images approximately 15-20 feet or further from the viewer do not vary sufficiently from each other to produce the three-dimensional effect. Hence, a view in depth or a three-dimensional effect, when obtained by the ordinary viewer of an object more than 15 or 20 feet distant, is based on the background of the viewer himself; that is, the experience he has had in viewing near and distant objects and the relationships among different planes of the objects which are viewed.
By separating the image which is transmitted to the eye into at least two separate planes containing respectively foreground and background images, the eye is induced to accept the composite image which is received as an image which appears to have depth and hence a three-dimensional quality. This is further enhanced by the fact that because the background image is spaced apparently further back from the foreground image by the distance from the light box to the mirror, the two different planes carrying the foreground and background images are not merely on two separate planes but the two planes are substantially separated from each other by an appreciable distance considering the distance from which the display is to be viewed. That is, a relatively small display having a mirror of the order of 15 square inches or of appropriate rectangular proportions would be viewed at a distance of perhaps up to 10 feet, while a larger display twice the size might be viewed at a substantially greater distance. Correspondingly, the spacing between the background image plane and the foreground image plane in the two different structures would be related to the size of the structure and thereby produce the same effect whether the display structure is large or small.
Many attempts have been made to obtain three-dimensional effects in display material. Such attempts have included the presentation of scenes taken from slightly different angles to take advantage of the interocular base. In most cases, such attempts have resulted in the need for interleaving strips of the picture on various backgrounds, including a corrugated or angled background so that different surfaces will be presented to each of the two eyes. This requires an exact positioning of the eyes or results in an abrupt series of changes in the picture viewed as a person passes by. Other attempts have been made by the utilization of mirrors to overlap images and attempt to produce the effect of seeing around the corner. Attempts have also been made with special types of viewers to present separate images or images which vary sufficiently from the normal experience, so that the eye could be confused. This relates to images on structures which polarize the light, requiring corresponding viewing devices and to devices which effectively separate the images presented to each eye and the angle of view available to each eye.